Copolyester carbonates are well known in the art for their relatively high mechanical and tensile strength as well as their distortion temperature under load. As with other engineering thermoplastics, the presence of various stabilizers and additives are usually necessary to stabilize or upgrade certain properties of a copolyestercarbonate while retaining the other properties of the resin to as great a degree as possible. It is of course important for the various additives and/or stabilizers to be essentially inert to the polymer and to have the various combinations of additives and/or stabilizers present in the composition have a total effect which is not significantly adverse to the polymer.
The color of a resin can be an important application feature. To obtain a specific resin color, particular additives known as pigments are generally employed. Many times a black color is achieved with the pigment carbon black.
A further significant feature of a resin application is its flammability rating. In order to qualify a resin for a certain application a certain inflammability rating must not be exceeded. Such a rating is often times achieved by adding a flame retardant additive to the resin.
Generally the presence of flame retardant additives and color pigments in the same resin composition does not bring about resin instability.